This invention relates to a dermatological preparation for use in the treatment of skin disorders and the like. More specifically, the invention relates to an exfoliating scrub that contains therapeutically effective amounts of niacinamide and exfoliating agents. The scrub is useful in the treatment of blemishes and inflammations caused by acne and similar conditions.
Acne is a skin condition that occurs most frequently among adolescents and is characterized by an excessive secretion of sebum or dermal oil from the sebaceous glands. Sebum normally reaches the skin surface through the duct of a hair follicle and a connected pore. During adolescence and at other times, the amount of sebum secreted by the pilosebaceous system may increase to the point where the follicular ducts and pores are obstructed, causing sebum to accumulate under the skin and producing a solidification of the sebum called a comedome. This in turn results in hyperkeratinization of the follicular opening, which can cause complete obstruction of the duct.
The dermatological manifestations of the obstruction of follicular ducts may include papules, pustules and cysts that are often associated with bacteria and secondary infection. These indications are generally referred to as acne. The blemishes that result from acne can range from mild skin irritation to severely disfiguring scarring in sever cases.
There are many treatments available for acne. For example, mild cases can be treated with dietary changes and careful washing with lotions containing benzoyl peroxide, and topical creams containing salicylic acid. Other treatment regimens, such as those suggested by Lerner in U.S. Pat. No. 5,556,887 recommend the use of vitamin A palmitate applied topically. There are many other useful treatment regimens for acne. The particular treatment used by an individual depends of course on many factors, including the severity of the condition.
One particularly useful therapeutic agent in the treatment of acne is niacinamide and several U.S. patents and other references disclose formulations for its effective use in treating acne and other dermatological disorders. Niacinamide is known to be beneficial in the treatment of dermatological lesions for many reasons, including its known anti-inflammatory properties and the fact that it does not induce bacterial resistance. One example of a reference that discloses the use of niacinamide in the treatment of acne is U.S. Pat. No. 4,505,896. In the ""896 patent, niacinamide (also commonly referred to as nicotinamide) is administered either orally or topically. The formulations disclosed in the ""896 patent include various other compounds known to be effective in the treatment of acne, including sulfur, salicylic acid, benzoyl peroxide and vitamin A.
The topical treatment regimen described in the ""896 follows the accepted traditional methods of using niacinamide. That is, the niacinamide is applied topically and is not removed, for instance, by washing. Other references use the same basic approach. For example, in their study entitled Topical Nictotinamide Compared With Clindamycin Gel in the Treatment of Inflammatory Acne Vulgaris, Shalita and Smith had patients apply a topical gel containing 4% niacinamide (nicotinamide) twice daily. (Int. J. Dermatol., 1995, V. 34, pp. 434-437.) The gel was not washed off. Likewise, in a study published in the United Kingdom in 1976, Comaish et al. describe the topical application of a cream containing 1% niacinamide. (Arch. Dermatology, Vol. 112, January 1976, pages 70-72.) Again, the cream was not removed.
As effective as the topical application of niacinamide is known to be, there are adverse side effects associated with it, including in some patients stinging, dryness and other discomfort. Applicant recognized these side effects and was granted U.S. Pat. No. 5,989,523, which is yet another example of a topical spray that contains niacinamide as an active ingredient. Like the references discussed above, this patent teaches that treatment of acne with topically applied niacinamide-containing products requires that the product be left on the skin for a significant period of time in order for the niacinamide to be therapeutically effective. Indeed, the topical spray disclosed in the ""523 patent is left on the patient""s skin. Recognizing the side effects that can occur as a direct result of the time that the niacinamide remains in contact with the skin, the formulation disclosed in the ""523 patent includes Aloe Vera extract and NaPCA. Aloe Vera extract has been found to have a direct effect in the treatment of acne as well as soothing qualities, and NaPCA acts as a moisturizer.
Topical application of niacinamide may often be beneficially combined with well known dermal cleansing techniques such as exfoliation. Human skin cells regularly die and are replaced with new cells. Exfoliation is a centuries-old process of removing the dead cells and excess accumulations of oil from the outermost layer of the skin. By removing the dead skin cells, the skin tends to look healthier and betterxe2x80x94lighter,smoother and more evenly textured. Exfoliation may also help to unclog pores and stimulate hydration of the skin. The treatment outlined in the ""523 patent recognizes the benefits of exfoliation and recommends that the area to be treated be scrubbed with an exfoliating scrub such as a conventional apricot scrub prior to application of the niacinamide-containing topical solution. In this process a standard exfoliating scrub is used to clean the skin. The scrub is then rinsed off and an aqueous liquid containing niacinamide is topically applied by spraying on the areas to be treated.
There are many different approaches to exfoliation. These include topically applied compounds that contain various acids such as hydroxy acids that dissolve the dead skin cells. The dead cells are washed off with the topically applied compounds. Another common method of exfoliation relies upon mechanical abrasion of the skin with heavy bristle brushes, scrubbers, loofas and the like. And yet another common method of exfoliating the skin is a combination of the two methods just mentioned in a topically applied exfoliating scrub that contains an abrasive material. Common abrasive materials included in such scrubs include ground apricot pits and walnut husks. These abrasive materials are generally delivered in a cream base. Exfoliation with these products involves application of the exfoliating agent to the skin, followed by gentle scrubbing and then cleansing to remove the exfoliating agent.
As noted above, niacinamide is known to have therapeutic benefits in the treatment of acne. However, traditional thinking has always been that the niacinamide had to be left on the skin for a significant period of time in order to be therapeutically effective. The present invention arises out of the unexpected and surprising results obtained by combining niacinamide into an appropriate carrier that also includes an abrasive compound to formulate an exfoliating scrub that is washed off immediately after use. Contrary to prior knowledge and the teachings of the prior art, the niacinamide included in the formulation of the present invention provides therapeutic benefits despite the fact that it is removed rapidly compared to prior topical application. By removing the active agent, niacinamide, from the skin immediately, the adverse reactions often associated with prolonged exposure to niacinamide are reduced or eliminated.